Central Bureau for Astronomical Telegrams
IAUC 5757: V1974 Cyg; 1993J
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Circular No. 5757
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
V1974 CYGNI
H. Dinerstein and R. Benjamin communicate: "Infrared spectroscopy
of V1974 Cyg (N Cyg 1992) by D. Lester, N. Gaffney, and B.
Smith at the McDonald Observatory 2.7-m reflector shows the appearance
of new infrared coronal lines, [Al IX] 2.040 microns and [S
IX] 1.250 microns. The ionization energy to create these ions are
285 and 328 eV, respectively. Both lines are clearly resolved from
neighboring lines. The [S IX] 1.250-micron line was tentatively
detected by Woodward and Greenhouse (IAUC 5653) with a reported
line strength of 0.08 times that of the adjacent Paschen-beta line.
This strength was consistent, however, with an identification as He
I 1.253 microns, which had been observed as early as 1992 June,
before the onset of the coronal phase. On 1993 Apr. 2.4 UT, we find
the strength of the 1.25-micron feature is a factor of 8 too strong
to be due to He I alone; it has increased to about 0.6 times the
strength of Paschen-beta. Therefore, we regard it as highly likely
that [S IX] is now present. Further confirmation that the level of
ionization in the ejecta has continued to increase since our previous
epoch of observations (1992 Dec. 10) is seen in the ratio [Si
VII] 2.47-microns/[Si VI] 1.96-microns, which increased from about
1.6 to 3.5 between 1992 December and 1993 April, while the absolute
fluxes of both lines dropped. These new infrared spectra supplement
and confirm the recent report of very high ionization species
([Fe X], [Ar X], and possibly [Fe XIV]) in the optical spectrum of
V1974 Cyg by Garnavich (IAUC 5746)."
SUPERNOVA 1993J IN NGC 3031
G. F. Lawrence and A. Paulson report the following infrared
photometry of SN 1993J obtained on Apr. 3.39 UT at the University
of Minnesota 0.76-m telescope using an InSb photometer (standard
infrared photometric techniques were employed with a 27" beamsize
and a 44" north/south throw; calibration was against the IRTF standard
stars HR 3888 and HR 5447): J = 10.91 +/- 0.05, H = 10.66 +/-
0.05, K = 10.48 +/- 0.08.
Visual magnitude estimates: Mar. 10.27 UT, [15.5 (W. Wren,
McDonald Observatory); Apr. 2.17, 11.4 (C. Spratt, Victoria, BC);
3.28, 11.5 (W. Johnson, Anza, CA); 4.03, 11.6 (P. Schmeer,
Bischmisheim, Germany); 5.03, 11.8 (J. Bortle, Stormville, NY); 5.271,
11.8 (R. Royer, Lakewood, CA); 6.26, 11.7 (W. G. Dillon, Missouri
City, TX); 7.23, 11.6 (Wren); 8.08, 11.4 (C. Heil, Andover, MA);
9.20, 11.5 (Dillon); 9.25, 11.4 (Royer).
1993 April 9 (5757) Daniel W. E. Green
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